refactor: update type hints for rex_type and types methods to improve clarity

Author: kosiew

python/datafusion/expr.py

@@ -648,23 +648,23 @@ def between(self, low: Any, high: Any, negated: bool = False) -> Expr:
 
         return Expr(self.expr.between(low.expr, high.expr, negated=negated))
 
-    def rex_type(self) -> "RexType":  # type: ignore[call-arg]
+    def rex_type(self) -> RexType:  # type: ignore[call-arg]
         """Return the Rex Type of this expression.
 
         A Rex (Row Expression) specifies a single row of data.That specification
         could include user defined functions or types. RexType identifies the
         row as one of the possible valid ``RexType``.
         """
-        return self.expr.rex_type()  # type: ignore
+        return self.expr.rex_type()
 
-    def types(self) -> "DataTypeMap":  # type: ignore[call-arg]
+    def types(self) -> DataTypeMap:  # type: ignore[call-arg]
         """Return the ``DataTypeMap``.
 
         Returns:
             DataTypeMap which represents the PythonType, Arrow DataType, and
             SqlType Enum which this expression represents.
         """
-        return self.expr.types()  # type: ignore
+        return self.expr.types()
 
     def python_value(self) -> Any:
         """Extracts the Expr value into a PyObject.